We are studying Photonic Integrated Circuits.　　　▷Japanese

Conventional AWG(Arrayed Waveguide Grating) have different waveguide length in each array to obtain the phase difference. To obtain the small wavelength space, large length difference is necessary, and device size will become large by increasing the number of channel. On the other hand, we have fabricated the straight type arrayed waveguide where the refractive index of each array waveguide are varied. If the refractive index of each array waveguide will be changed by QCSE etc., the optical 1×N deflector or wavelength switch will be realized.


To obtain the variable index arrayed waveguide, the selective area growth by MOVPE are carried out using a narrow SiO2 stripe mask pattern with a wide SiO2 masked region on one side. Since the source material does not adhere to SiO2, the vapor concentration is high above the wide masked region and lateral vapor diffusion occurs towards the striped openings in the mask pattern. As a result, the growth rate near the wide mask is high and the growth rate decreases gradually as the distance from wide mask. Then the size of QDs were gradually changed in the arrayed waveguide. Thus, the peak light emission wavelength for each of the array waveguides was different due to quantum size effects.